Mold assemblies currently available for injection or pressure molding articles are typically formed from rigid materials such as steel or other metal materials. In the past, such metal mold assemblies have generally consisted of multiple plate machined or, if in large quantity, cast molds. The molds are generally pre-heated to a desired temperature, clamped or compressed within an injection molding system, and injected with the desired molding material. The injection of the molding material is typically accomplished using an injection system having an injection press.
The production of such die molds having cavities for molding desired items is a time consuming and expensive process. Manufacture of the mold itself to the desired specification, may take many weeks. Additionally, where such fixed dimension molds are used for joining two or more separate molded pieces together, problems may result. For example, where it is desired to join elongate pieces of polymer material which are generally produced by another process, such as extrusion, such pieces may have individual size variations as great as 15% or more. Consistently forming a quality joint between pieces having such different sizes may be difficult to achieve, and may result in a molded article which does not meet desired aesthetic standards.
In the past, the joint molding of separate elongate pieces has been performed using machined or cast molds having spaces formed within the mold for receiving the pieces to be joined. Such molding processes have the distinct disadvantage of obtaining molded articles having an unattractive "step offs" or discontinuous joint lines between the elongate pieces and the molded joint material. Depending on the diameter and cross-sectional configuration of the elongate pieces, a separate mold may be required for joining different size and types of pieces.
Another disadvantage of conventional mold processes is that the molded articles produced typically require additional processing to remove flash from the articles. The formation of flash, and its removal, result in further increased costs due to wasted material, and the additional process of deflashing the article, or removing the excess material, and finishing the article. An additional quality control inspection of each article may also be required, which further increases the overall labor expense of the system.